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2015/2016 Sorghum Early Harvest Report

Contents

  1. Harvest Quality Highlights
  2. Introduction
  3. Quality Test Results
  4. Chemical Composition
  5. Physical Factors
  6. Testing Analysis Methods
  7. Moisture
  8. Chemical Composition
  9. Physical Factors
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III. QUALITY TEST RESULTS

A. Grade Factors

The U.S. Department of Agriculture’s Federal Grain Inspection Service (FGIS) has established numerical grades, definitions and standards for grains. The attributes which determine the numerical grades for sorghum are test weight, broken kernels and foreign material (BNFM), foreign material, total damage, and heat damage. The table for “U.S. Sorghum Grades and Grade Requirements” is provided on page 28 of this report.

SUMMARY: GRADE FACTORS AND MOISTURE

  • Early Harvest average test weight in 2015 was 57.9 lb/bu (74.5 kg/hl), above the minimum for U.S. No. 1 grade sorghum (57 lb/bu or 73.4 kg/hl).
  • The 2015 Early Harvest test weight values were distributed with 94% of the samples at or above the limit for U.S. No. 2 grade (55 lb/bu or 70.8 kg/hl).
  • Early Harvest average BNFM in the 2015 samples (1.4%) was well below the maximum for U.S. No. 1 grade (3.0%).
  • The 2015 Early Harvest BNFM values were all below the maximum for U.S. No. 2 grade (6%).
  • Early Harvest average foreign material in the 2015 samples (0.5%) was well below the maximum for U.S. No. 1 grade (1.0%).
  • In the 2015 Early Harvest samples, 98% contained less than the maximum foreign material allowable for U.S. No. 2 grade (2.0%).
  • Early Harvest average total damage in the 2015 samples (0.2%) was well below the maximum for U.S. No. 1 grade (2.0%).
  • Total damage in the 2015 Early Harvest samples was distributed with 98% having 5% or less (the maximum allowable for U.S. No. 2 grade).
  • There was no heat damage observed in any of the 2015 Early Harvest samples.
  • The absence of heat damage likely was due in part to recently-harvested samples coming directly from farm to elevator with minimal prior drying.
  • The Early Harvest moisture contents recorded at the elevator in the 2015 samples averaged 14.5% with a minimum value of 11.7% and a maximum value of 17.3%.

1. Test Weight

Test weight (kernel weight per standard container volume) is a measure of bulk density and is often used as a general indicator of overall quality and as a gauge of endosperm hardness for size reduction and value-added processing. High test weight sorghum will take up less storage space than the same weight of sorghum with a lower test weight. Test weight is initially impacted by genetic differences in the structure of the kernel. However, it is also affected by moisture content, method of drying, physical damage to the kernel (broken kernels and scuffed surfaces), foreign material in the sample, kernel size, stress during the growing season, and microbiological damage. When sampled and measured at the point of delivery from the farm at a given moisture content, high test weight generally indicates high quality, high percent of hard (or vitreous) endosperm and sound, clean sorghum. Test weight is highly correlated with kernel true density and reflects kernel hardness and kernel maturity.

RESULTS

  • Early Harvest average test weight in 2015 was 57.9 lb/bu (74.5 kg/hl), above the minimum for U.S. No. 1 grade (57 lb/bu or 73.4 kg/hl).
  • The test weight values for the 2015 Early Harvest samples had a standard deviation of 2.20 lb/bu (2.84 kg/hl).
  • The 2015 Early Harvest test weight values were distributed with 66% of the samples at or above the factor limit for U.S. No. 1 grade and 94% of the samples at or above the limit for U.S. No. 2 grade (55 lb/bu or 70.8 kg/hl).

2. Broken Kernels and Foreign Material (BNFM)

Broken kernels and foreign material (BNFM) is an indicator of the amount of clean, sound sorghum available for feed and processing. The lower the percentage of BNFM, the less foreign material and/or fewer broken kernels are in a sample. Higher levels of BNFM in farm-originated samples generally stem from combine settings and/or weed seeds in the feld. BNFM levels will normally increase during drying and handling, depending on the methods used and the soundness of the kernels. Stress crack formation during dry down or during mechanical drying after harvest will also result in an increase in broken kernels and BNFM during subsequent handling.

RESULTS

  • Early Harvest average BNFM in the 2015 samples (1.4%) was well below the maximum for U.S. No. 1 grade (3.0%).
  • The BNFM values for the 2015 Early Harvest samples had a standard deviation of 0.62%.
  • The 2015 Early Harvest BNFM values were all below the maximum for U.S. No. 2 grade (6%), with 92% of the samples also below the maximum for U.S. No. 1 grade (3%).

3. Foreign Material

Foreign material, a subset of BNFM, is of importance because it has little feed or processing value. It is also generally higher in moisture content than the sorghum and therefore creates a potential for deterioration of sorghum quality during storage. Foreign material also contributes to the spoutline and has the possibility of creating more quality problems and damage because of its higher moisture level, as mentioned above.

RESULTS

  • Foreign material in the Early Harvest samples averaged 0.5% in 2015, well below the maximum value of 1.0% for U.S. No. 1 grade.
  • The foreign material values for the 2015 Early Harvest samples had a standard deviation of 0.27%.
  • In the 2015 Early Harvest samples, 98% of the samples contained less than the maximum foreign material allowable for U.S. No. 2 grade (2.0%).

4. Total Damage

Total damage is the percentage of kernels and pieces of kernels that are visually damaged in some way, including badly ground-damaged, badly weather-damaged, diseased, frost-damaged, germ-damaged, heat-damaged, insect-bored, mold-damaged, sprout-damaged, or otherwise materially damaged. Most of these types of damage result in some sort of discoloration or change in kernel texture. Damage does not include broken pieces of grain that are otherwise normal in appearance.

Mold damage is usually associated with higher than desired moisture contents and temperatures during growth and/or in storage. Mold damage and the associated potential for development of mycotoxins are the damage factors of greatest concern. Mold damage can occur prior to harvest as well as during temporary storage at high moisture and high temperature levels before delivery.

RESULTS

  • Total damage in the Early Harvest samples averaged 0.2% in 2015, well below the limit for U.S. No. 1 grade (2%).
  • The total damage values for the 2015 Early Harvest samples had a standard deviation of 0.38%.
  • Total damage in the 2015 Early Harvest samples was distributed with 96% of the samples having 2% or less damaged kernels (the maximum allowable for U.S. No. 1 grade), and 98% having 5% or less (the maximum allowable for U.S. No. 2 grade).

5. Heat Damage

Heat damage is a subset of total damage and has separate allowances in the U.S. Grade Standards. Heat damage can be caused by microbiological activity in warm, moist grain or by high heat applied during drying. Heat damage is seldom present in sorghum delivered at harvest directly from farms.

RESULTS

  • There was no heat damage observed in any of the samples.
  • The absence of heat damage likely was due in part to recently-harvested samples coming directly from farm to elevator with minimal prior drying.

B. Moisture

Moisture content (water weight in kernels per total weight of kernels (i.e., water plus dry matter)) is reported on official grade certificates, but does not determine which numerical grade will be assigned to the sample. Moisture content affects the amount of dry matter being sold and purchased. Moisture is also an indicator for potential drying, has potential implications for storability, and affects test weight. Higher moisture content at harvest increases the chance of kernel damage occurring during harvesting and drying. Moisture content and the amount of mechanical drying required will also affect stress crack formation, breakage, and germination. Extremely wet kernels may be a precursor to high mold damage later in storage or transport. While the weather during the growing season affects yield and the development of the kernels, harvest moisture is influenced largely by the timing of harvest and harvest weather conditions.

RESULTS

  • The Early Harvest moisture contents recorded at the elevator in the 2015 samples averaged 14.5%, with a minimum value of 11.7% and a maximum value of 17.3%.
  • The moisture content values for the 2015 Early Harvest samples had a standard deviation of 0.88%.
  • The 2015 moisture values were distributed with only 32% of the samples containing 14% or less moisture. This is the base moisture used by most elevators for discounts and is a level considered safe for storage for short periods during low winter-time temperatures. Drying may have been considered for 68% of the 2015 Early Harvest samples.